This invention is directed to improvements in bicycles. It is particularly concerned with a bicycle with a frame having an extension rearwardly of and beyond its rear wheel, in which extension a pedal driven crankshaft together with means for driving the rear wheel is supported.
A desirable advantage of a bicycle of this construction is that it enables the rider to obtain a substantially full length prone position when pedalling, and enables him to maintain this riding position with reasonable comfort.
In bicycling, particularly when it is desired to obtain added speed, it has been found that this can be accomplished if the rider assumes a substantially prone torso position so that his body will present reduced resistance to opposing air forces.
However, the degree of reduction in resistance to air forces that can be obtained in this manner is presently limited, because the structure of the conventional bicycle does not enable the rider to obtain a substantially full length prone position when pedalling. In the conventional bicycle the pedal driven crankshaft and the chain drive sprocket carried by it are located in an area of the frame forwardly of the rear wheel and below the saddle. This construction enables the torso of the rider but not his legs to obtain a substantially prone position. Accordingly, his legs depend at about right angles to the prone torso and thereby impede free flow of opposing air forces. Further, this depending disposition of the legs relative to the prone torso creates a cramped condition of body and legs which interferes with the comfort of the rider.
In the present invention the bicycle is structured in its frame so as to support the pedal driven crankshaft and the associated drive means beyond and rearwardly of the rear wheel. By means of this arrangement the rider is enabled to obtain a substantially full length prone position while pendalling. This allows opposing air forces to more easily flow over the rider's body and thereby present less impedance to forward movement of the bicycle than would otherwise be provided by the position obtained by the rider on a conventional bicycle. Further, by means of this arrangement the legs of the rider are disposed substantially in line with his torso, whereby the cramped condition mentioned earlier is avoided.
A main feature of the invention is a bicycle frame supporting a front and a rear wheel, and having a portion of its frame extending rearwardly of an beyond the rear wheel, in the end of which extended portion is supported a pedal driven crankshaft and a drive sprocket connected by an endless drive chain to the usual sprocket gear carried by the rear wheel.
A further feature of the invention is exhibited in a modified form thereof in which the extension of the frame beyond and rearwardly of the rear wheel is in the form of a separable attachment or accessory unit. The pedal driven crankshaft and drive sprocket are supported in this unit; and the unit is provided withn suitable means whereby it may be removably attached to the rear of a conventional frame of a bicycle.
A further advantage of this modified form is that it enables the existing endless drive chain of the associated bicycle to be drivingly connected, at the election of the rider, to either the existing drive sprocket of the bicycle or to the drive sprocket of the accessory unit. By means of this arrangement the rider may elect to ride the bicycle in conventional upright manner, or in the prone manner enabled by the accessory unit.
Another feature of the invention is a saddle which is elongated to provide a degree of support for the rider's torso in the prone position; and it is adjustable angularly, as needed, to provide a desirable confortable engagement with the rider's body.
The foregoing mentioned structures, features and advantages of the invention will become increasingly apparent as this specification unfolds in greater detail, and as it is read in conjunction with the accompanying drawing wherein an embodiment of the invention is shown. However, it is to be expressly understood that the drawing is for purposes of illustration; and it is not to be construed as limiting the scope of the invention.